ABINIT Discussion Forums

Hi,
I'm unclear as to the interoperation of libXC, abinit, and atompaw. I have built abinit 6.5.2 with the libXC plug-in, and have also built the new atompaw with libxc support. Using atompaw I successfully generated PAW sets for Si and O using PBE and PBEsol, but abinit won't run them. For example, with PBE, ixc gets set to -101130, but then the code stops with


drivexc : ERROR -
At least one of the functionals is a GGA or a MGGA,
but not all the necessary arrays are present.
ixc=-101130 nvxcdgr= 0 ngr2= 1
-P-0000
-P-0000 leave_new : decision taken to exit ...

Is PAW within abinit simply not yet compatible with the range of libXC inputs, even though atompaw can make them?

thanks,
Joe

OK, I *think* I fixed the bug...

in size_dvxc.F90, line 90, the if statement included a test for ixc < 0, this was overriding the next test for ixc < 0; I removed the first of these tests and let the second test handle the ixc < 0 case. pbe and pbesol seem to work now, hope all else is still ok...more updates as warranted...

Hi Joe,

I think that MetaGGA is not yet compatible with PAW because the calculation of the kinetic energy density is not yet implemented in this case (it is in norm conserving).

David

Thanks, David--that is also the case in atompaw, where it explicit that only LDA and GGA XC models are allowed. The fix I made in size_dvxc (and uploaded to my 6.4.3-public branch) seems to be what was needed.

Hi Joe,

Thanks for the bug correction.
This must have been introduced recently; libXC and PAW worked some months ago...
We should provide an automatic test for libXC+PAW.

Marc

Hi Marc,
I can provide a test no problem. By the way have you ever tried atompaw with the AM05 XC?

Joe

Not yet.
Vacation time ended this morning...

Hello, abinit team,

I want to use a PAW data generated with a XC functional from the Libxc library. But I get the message

pawxcm.F90:199:WARNING
Note that no xc is applied (ixc=0)

I found that the internal variable xclevel is set to 0 instead of 1 during the calculation. And according invars2.F90, xc level is 1 only for 1< ixc < 30 or 30 < ixc < 39. But for Libxc I need a negative ixc. Why is xclevel = 0 for Libxc functionals ?

And most of the over 4000 WARNINGs contain this message.

Thanks in advance!

Ider

This bug has been corrected.
It is specific to LDA (you can use GGA with libXC).

To be released before the end of the month (v6.8)...